In automatic control of prescribed equipment, an automatic control signal is outputted on the basis of, for example, a target value (a command value) and a detected value so that actions of the above-described equipment become stable in a desired condition, whereby a driving device is controlled.
Some apparatuses which perform such automatic control are provided with a manual intervention unit operated by humans, whereby actions of the above-described equipment can be manually regulated. In such controllers, in the case where an action of equipment has deviated abruptly from a target value due to, for example, a disturbance or the like, an operator operates a manual intervention unit, whereby a manual control signal is outputted and the action of the equipment is manually corrected.
As a conventional art of controllers having such functions, there have been proposed controllers for performing speed control of the rolls of a rolling mill stand which are configured to be capable of manually regulating the speed of the rolls (refer to Patent Literature 1, for example).